What causes an iPhone to overheat and lose battery quickly
An iPhone that runs hot and loses battery in hours instead of a full day is usually running one or more apps or processes that demand constant power. The most common culprits are location services left on, background app refresh pulling data constantly, a failing battery that can no longer hold a charge, or an app with a bug that makes it use the processor continuously even when you're not looking at it.
Heat and fast battery drain almost always go together because they have the same root cause: something is working hard inside the phone. When the processor, modem, or graphics chip runs at high load, it burns power and generates heat as a byproduct. If you see both symptoms at once, start by identifying what's running, not by assuming the battery itself is dead.
Key Takeaways
- Location services, background app refresh, and push notifications left on for many apps will drain battery and generate heat even when you're not using the phone.
- A single app with a bug or a memory leak can cause the processor to run constantly; force-closing it usually stops the heat and battery drain when ready.
- Batteries degrade with age and charge cycles, and a battery below 80 percent health will drain noticeably faster and may run hotter under load.
- Checking Settings > Battery > Battery Health & Charging tells you whether your battery is the problem or whether an app or setting is.
- If the phone is hot to the touch and losing 10 percent or more per hour, stop using it and let it cool before troubleshooting further.
How to find which app is draining your battery
Open Settings, tap Battery, then Battery Usage. This screen shows you which apps have used the most power in the last 24 hours or the last 10 days. Look for any app that has used more than 20 to 30 percent of your battery when you haven't been using it much. If an app shows high usage but you barely opened it, that app is likely running in the background and causing the drain.
Force-close the app by swiping up from the bottom of the screen (or swiping down from the top right on newer iPhones) to open the app switcher, then swipe up on the app's card to close it. If the battery drain and heat stop after you close it, you've found the problem. Uninstall the app or check the App Store for an update—developers often release fixes for battery-draining bugs.
If no single app stands out, look at the list for apps you don't use anymore and delete them. Then check Settings > General > Background App Refresh and turn it off for apps that don't need to update in the background—news apps, social media, and games rarely need it.
Location services and background activity eating power
Location services use the GPS chip, which is one of the most power-hungry components in an iPhone. If you have location turned on for many apps, the phone is constantly calculating your position and sending it to those apps, even when they're closed. Open Settings > Privacy & Security > Location Services and scroll through the list. For each app, tap it and change the setting from "Always" or "While Using" to "Never" unless the app genuinely needs your location to work.
Maps, weather, and find-my-friends apps need location. Social media, email, and games usually don't. Maps in particular should be set to "While Using" rather than "Always" so it only uses GPS when you're actively navigating.
Push notifications also drain battery because the phone has to wake up and check for new messages constantly. Go to Settings > Notifications and turn off notifications for apps that don't need them. You can always check those apps manually when you want to.
Checking your battery health
An iPhone battery degrades over time. After 500 charge cycles (a full discharge and recharge), most iPhone batteries drop to about 80 percent of their original capacity. At that point, the phone drains noticeably faster and may run hotter under heavy use because the battery can't deliver power as efficiently.
Open Settings > Battery > Battery Health & Charging. Look at the "Maximum Capacity" number. If it's above 80 percent, your battery is still healthy and the drain is likely caused by an app or setting. If it's below 80 percent—especially below 70 percent—the battery itself is degraded and a replacement will restore normal battery life and heat levels.
The same screen shows "Condition" at the bottom. If it says anything other than "Normal," Apple has detected a problem with the battery and recommends service. You can replace the battery through Apple or an authorized repair shop; the cost varies by model but typically runs between $50 and $100.
Temporary steps to cool the phone and stop the drain
If your iPhone is hot enough to be uncomfortable to hold, stop using it when ready and let it cool. A phone that's too hot can damage the battery further and may throttle (slow down the processor) to protect itself, which will make it feel sluggish.
Remove the case if you're using one—cases trap heat. Turn off Wi-Fi and Bluetooth if you're not using them. Close all open apps by swiping up in the app switcher. If the phone is still hot after 10 minutes of sitting idle, there's likely a background process or app causing the problem, and you should move to the troubleshooting steps above.
Avoid charging the phone while it's hot. Charging generates additional heat, and a hot battery charges more slowly and degrades faster. Wait until the phone has cooled to room temperature before plugging it in.
When to restart or reset your iPhone
If you've turned off background app refresh, location services, and notifications but the phone is still hot and draining fast, restart it. Press and hold the power button and either volume button until the power-off slider appears, then slide to power off. Wait 30 seconds, then press the power button again to turn it back on. A restart clears temporary files and stops any stuck processes.
If the problem persists after a restart, the next step is to check for a software update. Go to Settings > General > Software Update. Apple sometimes releases updates that fix battery-draining bugs. Install any available update and restart the phone again.
If you've done all of this and the phone is still losing 10 percent or more per hour, the battery is likely the problem. At that point, a battery replacement is the most reliable fix. Do not attempt to replace the battery yourself—opening an iPhone risks damaging the screen and other components. Take it to Apple or an authorized repair shop.
Frequently Asked Questions
Is it safe to use my iPhone while it's hot?
No. Stop using it and let it cool. A phone that's too hot can damage the battery permanently and may shut itself down to protect the internal components. If it's hot to the touch, set it down in a cool place and wait at least 10 minutes before using it again.
Why is my iPhone hot even when I'm not using it?
An app is running in the background. Check Battery Usage in Settings > Battery to see which app is using the most power, then force-close it or uninstall it. Also check that location services and background app refresh are turned off for apps that don't need them.
Does a low-power mode help with battery drain and heat?
Yes, temporarily. Low-Power Mode reduces processor speed and background activity, which slows battery drain and heat generation. Turn it on in Settings > Battery, but it's not a permanent fix—it just buys you time to find and fix the real problem, whether that's an app or a failing battery.
Can I replace my iPhone battery myself?
Not safely. Opening an iPhone risks damaging the screen, water seals, and other components. Take it to Apple or an authorized repair shop. Replacement usually takes one to two hours and costs between $50 and $100 depending on the model.
What if my iPhone is hot and the battery percentage jumps around?
That's a sign the battery is failing. The phone can no longer accurately measure how much charge is left, and the battery can't deliver stable power. Check Battery Health in Settings > Battery > Battery Health & Charging. If the maximum capacity is below 70 percent, schedule a battery replacement.